Not many people claim to have a direct line, but Prime Minister John Key says he has such a good relationship with Barack Obama he can call him at will - and the United States President will pick up the phone.

Mr Key's comment came in a speech before 300 diplomats and former politicians at the New Zealand Institute of International Affairs.

He said an extensive travel schedule had helped him form strong bonds with a number of world leaders, including Mr Obama.

"In the first instance what we get is personal relationships, so if I needed to ring up the President of the United States I could do that and he would take my call.

"And that's partly because I have developed a personal relationship from getting to know him at Apec or the nuclear security summit."

Mr Key and Mr Obama have met, spoken and written to each other since coming to office in late 2008 and early 2009 respectively.

They first spoke in May last year for 15 minutes on a pre-arranged telephone call that ended up on a first-name basis.

They met for the first time at the United Nations last September at lunch and at dinner.

They met again in November at Apec in Singapore where Mr Obama invited Mr Key to the nuclear summit in Washington this year, hosted by Mr Obama.

They corresponded in the lead-up to the select summit attended by only 40 leaders.

And during the two days it was on in April, they had plenty of opportunity to converse.

It is likely that Mr Key will make an official visit to the White House next year.

During his speech to the institute in Wellington yesterday, Mr Key talked about the importance of different countries to New Zealand's economy and said travel had to be a high priority for prime ministers.

"I'll tell you something for nothing, it's going to get worse for every New Zealand Prime Minister, it will not get better. No New Zealand Prime Minister will travel less than I am. In the future they will travel more.

"And any journalist that doesn't like it will just have to get over themselves. That's the way it is."

Mr Key said multilateral partnerships such as the Asia-Pacific Economic Co-operation (Apec), the Pacific Islands Forum, Commonwealth Heads of Government Meeting, United Nations and the Association of Southeast Asian Nations were serious commitments from which New Zealand benefited.

NZPA, staff reporter